You should consider as we go that this was how I built
a bio-filter for my pond. Assuming you are attempting
a DIY approach you will obviously need to adapt
it to your situation.
I already had a small filter (Hozelock
Cyprio Bio-Force 2200 UVC), and a pump (Hozelock Cyprio
I also wanted the water coming out of
the filters to go into the back of the terracotta urn
(via pipes going into holes I drilled in the back of
the clay urn), spill out of the mouth of the urn, down
the waterfall and the stream.
So consider your own needs,
and plan accordingly. I find this works for my size of
pond (400 gallons), but you may need to upsize!
The Big Search
A key factor in my minds eye was to use a big plastic
flower pot, which should look nicer than a big black Rubbermaid
tank so typically used for a Skippy style filter - not
so obtrusive, would be easy to drill holes in, and
a cylinder contains more volume than a square or rectangular
tank of similar size. And as mentioned previously water
swirls inside it more naturally. So I visited a couple
of garden centres to see what I could find.
Hmm. Nice big pot.....
....but the patterning would be awkward to drill through
and create a waterproof seal.
An even bigger pot. More like the size I want......
...and the patterning has enough space around to allow
drilling and the water outlets to sit flush.
Another pot, but smaller, and it had extrusions with
holes in the bottom making it useless to hold water
Excellent, I have also found a plastic sieve which
fitted perfectly in the bottom of my chosen pot which
would sit on top of, thereby creating a gap for the
water vortex underneath.
Basically I now simply needed a variety of pipe fittings,
clips and hoses to work with:-
- Big pot 47cm diameter across
the top (£20)
- 25mm Flexible hose (in fact the black hose shown here
was very stiff, and didn't get used in the end, £6 wasted!
I got some other more flexible hose later on 2m of 40mm
hose to exit the filter, and 3m of 25mm to enter the
- Plastic sieve (£2.50)
- 40mm U-Bend piping kit (all necessary rubber seals,
and fittings included, £5)
- 40mm Shower drain unit (one of the more expensive
- 25mm black double-ended hose connector (£4, I got
this to join existing piping at my Bio-Force UVC filter
when I excluded it from the loop. In fact I put
the Bio-Force back in as a solids pre-filter, so this
connector was not used after all)
- 3 x 22mm pipe right-angle bends, push fit (99p each)
- 2 x 22mm pipe T-pieces, push fit (99p each)
- 1 x 22mm pipe tank inlet, straight-through (£1.25)
- 2 x 22mm pipe tank overflow, right-angle bends (£1.25
each) NB. one of these was later replaced with a 40mm
tank outlet, see below.
- 4 x 18-30mm metal screw-adjust "Jubilee" hose clips
(50p each pack)
- 22mm plastic water pipe, 2m length (£1.50)
- Also (not pictured),
- A pack of Pond Bacteria culture
to help start maturing filter,
- a 40mm tank overflow
outlet (I used this to replace one of the 22mm
ones later on to ensure good exit flow from the
to the pond)
- Fernox LS-X jointing compound and leak sealer
glue (dries rubbery, acetic acid (vinegar) base
The shower-drain unit by coincidence matched exactly the
size of the recess in the bottom of the pot.....
Inlet & Overflows
Consider the angles of where you want your pipework to enter
and exit the bio-filter, i.e. where are your pump, pre-filter,
and returns back to the pond located? This should dictate
the orientation of your bio-filter tank, how the pipes
come to it, and where you intend to put buckets/watering-cans when
emptying the filter, or even where the waste water will go
to if you're just emptying straight onto the ground. Plan
and mark out where you want the inlets and outlets to go. In
my case I found that this was partly dictated by the raised
flower pattern decoration on the sides of the big pot,
because I had to drill in between on the flat parts.
drill and fit the inlet and overflows.
I would recommend
not doing things up too tight or sealing them during the
experimental stage to allow for adjustments to be made.
I created 2
because I knew that my pump would force more water into
the tank under pressure than would be allowed out under
gravity. In fact,
much later on I replaced one of the 22mm outlets
with a much larger bore 40mm outlet and flexible hose,
which works much better at letting the water out. I
was concerned about these narrow 22mm pipes becoming
blocked and causing
the bio-filter to overflow, so losing all the water from
the pond with potentially disastrous consequences!!!
Main Flush Drain
Next task was to fit the shower-drain unit, and measure
and cut the pipework to create my main drain
My idea was to have the pipe clipped against the side of
tank. I lubricated the rubber seals for the pipework
with vaseline, not only to provide a good watertight seal,
the whole pipework to be unclipped, and rotated easily
to allow emptying of the filter. I figured that
pipe of this bore would allow the water to exit rapidly,
any muck out quickly. In practice this works a treat,
and allows a very quick cleanout every day or 2,
taking no longer than 30 seconds, dumping into a watering
still running. Easy maintenance!
length of the pipe allows me to lower it over a watering-can
to water plants around the garden, or to fill up a bucket
for cleaning of the pre-filter media or the bio-filter
also because the top of the pipe is open, I can put new
Bacteria Culture into the top, and literally "inject" the
bacteria right into the heart of the filter, by pouring
to the pipe. All will become clear!
Another thing to mention is that the shower drain has
a 6-spoke plughole centre (see earlier picture). It is
possible to remove this, and its shower trap shaft. This
would normally form the trap for any hair and muck which
normally goes down a plug hole, but I found that this
just got blocked up with sediment or any algae/blanket-weed so
I removed it altogether. This improves draining the
bio-filter quite substantially, and also allows a clearer
for sediment to drift down into the main body of the
trap during the day, ready to be flushed out the next
time I clean it.
Note that due to the protrusion of the shower-drain unit
and pipework at the base of the tank it is necessary to
have a sturdy platform to straddle each side of it, and
support the weight of the tank and water. This is achieved
very nicely by two house bricks sat on top of a level paving
slab, which give a solid sturdy base. When the tank is
filled with water it is very heavy!
The main drain assembled. The point of rotation of the
P-trap (the part I am holding in the above photo) is on
the axis where the pipe goes into the shower-drain unit.
I unclip the pipe from the side of the tank, and pivot
it left and down. The water will then flow out of the
main riser pipe (see pictures near bottom of this page
in the Cleaning the Bio-Filter section,
also note in those pictures that I have flipped the
P-trap the other way around). The
P-trap allows me to rotate the drain downward to empty
the bio-filter into a waiting bucket. I smear some vaseline
on the rubber grommet in the P-trap so it will rotate easily.
I suppose instead of a P-trap it could have been just a
normal 90 degree bend, but my thinking was that the P-trap
additional room for sediment to settle down into, ready
for when I flush it out. Also it came as part of the pipework
kit I bought from the store so it seemed to make sense
to make use of it.
The tank is now filled with water as a test to see whats
Hmm. Plenty! A leak is not good here. Again while I was
still constructing the whole thing I didn't worry too much
about sealing, but once I had the design and any tweaking
done, I used some Fernox plumbers jointing compound. This
is wierd stuff which is clear, smells of vinegar (because
acetic acid to help the curing process), and sets on contact
with water. It doesn't seem to hurt your skin so even
though its not pleasant I used my fingers to spread it
surfaces - I used plenty - rather be sure than sorry.
Keep it away from your eyes though, and wash your hands
well after using it!
When set it is rubbery and pliable, and creates a very
the shower-drain unit, and the main drain pipework were
very tight and well sealed, either with Fernox where I
didn't want it moving, or with vaseline where I intend
the whole pipe structure to rotate when emptying the filter.
Note also that I used the Fernox on the inside where the
nut & bolt
are holding the pipe clip to the tank, to make it both
watertight, and help prevent corrosion.
There is one thing I am wondering about with my design.
Whether there is a risk of the bottom drain/u-bend freezing
in winter, and expanding so causing leakage,
or at worst total flood-out of the pond. Hmmmm!? Perhaps
there won't be a need to run the bio-filter in winter for
my size of pond and fish? Or perhaps the constant flow
of water will keep it from freezing? This is something
I will have to keep a cautious eye on.
Update: I had no problems this winter just gone, even
with the top of the pond actually freezing over. This is
a British winter though! Mild compared to some countries.
Obviously the water level in the tank also rises in the
pipe on the outside, so the length of the rising pipe must
be sufficient to always be above the maximum expected level
of water inside the tank, otherwise it would overflow from
the top of the up-pipe! Not what you want!
At this stage
I found that there was some natural give and droop in the
due to the rubber seals, and the added weight of the water
in the pipe, which the plastic clip holding the pipe against
the tank could not support. To cure this I added a couple
of screws to help hold the pipe up on the topside of the
clip. See below. At the time I kicked myself for not cutting
the pipe longer, but in practice there is just sufficient
height for it not to overflow. The water goes out of the
proper outlets as intended.
Update: I have since replaced this pipe
with a much longer section, that now comes about 10cm above
the top of the bio-filter
pot. What I have found is that when the pump is forcing
water down into the vortex chamber section at the base
of the filter, there is a slightly increased water pressure
which results in this drain pipe having a slightly higher
water-level. It is much better to have too much height
of pipe than too little.
Settlement Chamber Vortex Swirler
Note that this build section was modified later
on when I added the venturi. Please read the whole
process before starting to cut any pipework! (Unless
you don't want to build the venturi).
for the vortex settlement chamber was based on the idea
proposed by the Skippy Filter, where the water is
fed to the bottom of the filter under pressure and out
of two pipes in opposing directions to create a circular
swirling vortex motion. The idea being that:-
- its better to keep muck out of the bio-filter, so
this settlement chamber hopefully catches anything
let through by the pre-filter
- the water is distributed evenly
around the vortex settlement chamber before moving
upward through the garden sieve
- a whirlpool or vortex action causes muck and sediment
to move to the centre and settle downward into the
ready for expulsion when the filter is emptied
This is the basic layout - a down pipe goes into a T-piece,
then outward to the right-angle bends to create a clockwise
motion of the water.
Here is the swirler measured, cut and assembled. Note
the slight downward angle at each end to help move sediment
to the floor of the chamber.
Now get the sieve. Fairly ordinary. 36cm diameter.
the lucky combination of this size of sieve and the
of the main tank, when the sieve is placed in the tank
as far down as it will go and rests on the sides, there
is still about a 2 inch gap between the bottom
of the sieve
Cut out a segment from the centre of the sieve. This
segment, I found out once again by chance, was a very
snug fit for 22mm pipe to pass through. How lucky am
And now the swirler can be put in place through the
sieve. The T-piece fits nicely against the bottom of the
sieve without going through the cut-out segment.
Note in the picture below that the top of the swirler
is against the bottom of the sieve, with about a one
and half-inch gap from its underside to the bottom of
put the swirler/sieve assembly into the tank and measure
the rising pipe length to the pump/pre-filter flow inlet
After cutting the pipe, put a right-angle bend on
Then measure and cut the pipe for the feed from inlet
to the down-pipe, and fit in place......
Some more testing to see how it all works, check water
levels, overflows, and swirler action.
So far so good! Although I'm a bit dubious about the
very stiff black pipe I've got. Think I need to get something
testing and filling, I discovered that air trapped
under the top lip of the sieve was sufficient to cause
it to float upward, so I drilled several holes around
its circumference. Not too many because I want the
majority of the water to be channelled up mainly
bottom of the sieve, not through
holes at the outer side of the
Finally all that is required is to
assemble everything, put the filter media in, start
the pump and check for leaks.
Again I did a test
run before securing everything, because once in place
I found that there were several small leaks
around the jubilee clips
used to connect the hoses to the inlets and outlets.
daub of Fernox plumbers
glue fixed the leaks. Also note in this photo that
I have fitted better flexible hosing (I think its
called Flexihose) rather than the very stiff hose
I got initially.
Once you are happy with everything, put the filter
media in (see next section).
The Big Green Scrub-Up! (Filter Media)
Skippy's site recommends industrial size green
the filter media. Lots of people seem to use and
recommend this stuff. Despite its rather innocent
normal purpose, it has a high surface to volume
ratio of 300:1 making it a very good surface for
bacteria to colonise.
It was quite hard to find a supplier of the big thick pads.
I did not use the circular pads used on floor cleaning
They were quite expensive, and I needed quite a lot. A
friend offered me a whole load of these free, but they
had been used and though he cleans them afterwards I was
concerned that they would contain floor cleaners and traces
of dirt that would either prevent the bacteria growing,
or worse could poison my fish!
It amazed me how much people charge for this stuff!
Normally housewives buy this from their supermarket
in a little pack of 5 for their housework and it
so they don't mind paying a couple of quid. Skippys
supply it in bulk at a very reasonable price, but
they are based in the USA.
After much searching I
found a reputable Internet company in Scotland
Direct who are suppliers to the
butchers trade. Butchers have to clean their work
surfaces very regularly, so Scobies supply these
large size scrubbers in bulk.
1 box of 120 pads which was plenty for the task
I had about 50 pads leftover).
It arrived 2 days
later. These scouring pads are
230 x 150mm x 8mm (9 x 6 x 1/4 inch), designed
suitable for all cleaning applications
- and ponds! Now if they are suitable for cleaning
surfaces used for preparing meat on, then I think
they will be alright for my fish! They probably
aren't quite as thick as the ones supplied by Skippy's
(which I think are more like 15mm), but they seem
to be perfectly adequate for the job and are slightly
thicker than the usual dishwashing green scouring
pads (that supermarkets charge the earth for!!).
At Scobies just go to the Sundries, Disposables
section where you will find them, or click this
At the time they cost £14.95 for the box, the total order was about £23 after
VAT and UK post & packing.
Update: Recently I was told that Scobies are having stocking
issues with these pads. I am trying to find out more from Scobies currently,
but in the meantime
I have located an alternative stockist who charges a bit more. They are Akro
Services and you can find their Green Scourer Scrubbies Pads (product
F959 currently at £2.75 box of 10) by clicking here:
Another supplier that I have been told about is
Ace Janitorial Supplies Ltd in
Sheffield, UK. (Tel: Paul Cullumbine on 0114 244
4474 or 0114 244 5035),
They supply 9x6 inch contract scouring pads in
boxes of 50 for £6.60 inc. VAT
per box. A friend of mine who has a much larger
pond, built two
filters using two 80litre bins from his local B&Q
store and based on my
one into the other for his
3000 gallon pond. He bought 10
boxes initially but later found that 6 boxes were
sufficient for his two 80 litre bins.
Also thanks to Andy who let me know about this
of 20 for £2.99 inc VAT (multi colours
To load the filter, I simply set the water running
through the tank, so that I knew the top level
to fill up to with the filter media. then simply
up the pads. They are good size pads, so most I cut into quarter size,
while some I only cut in half. As they went in,
I gently pushed them down to soak
them, and get them to fill all the gaps nicely.
The idea with using these is
that they create natural voids between them which the water can track between,
so the filter won't become blocked by any solids which get through from the
pre-filter. The intention of the
media is to slow, not block, the passage of water through so as to maximise
time the water is in contact with the bacteria
who make their home on each pad.
Once finished there was still a good flow
of water through, which after exiting the filter still gave a nice gush
of water from the terracotta urn, and down my stream.
I also cut a plastic carton to fit around the main
overflow to prevent the pads from going over
it and blocking it up.
It turned out that this
wasn't really necessary, because once wet, the
pads pretty much stay where they are put.
One thing I like about the
main drain is that it can also act as an "inlet" to
To get the filter started I poured
the contents of a
into the top
of the main drain and then poured enough pond
water (NOT tap water) into the pipe to flush
the bacteria powder through
into the heart of the filter (probably a gallon
This was done while the pump was running and
will help jump-start the new bacteria forming
in the filter, and the pond. This can be repeated
with some more perhaps 1 week later, according
to the instructions provided with the bacteria,
and thereafter probably on a monthly basis to
ensure good strong growth of the bacteria throughout
Click here for more information about Bacteria
Cultures and products suitable for Bio-Filters.
Every Little Bit Helps
||The box of 120 filter media I got from Scobies
Direct had plenty of pads to fill the filter,
and then some. I figured that I could extend
the bacteria colony beyond the actual bio-filter.
Anaerobic bacteria live anywhere in the pond,
in the silt, on stones, on the sides, on plant
roots. The bio-filter is simply their main home.
So why not give them additional living quarters
in the terracotta urn at the head of the waterfall?
So I simply cut up and added a stack of
the scouring pads into the urn as well. This should mean there
are even more bacteria available to purify the
The photo below shows the Hozelock Cyprio
Bio-Force 2200+UVC filter hiding under
a curry-plant. Click here for
Cyprio site. I mentioned on the Introduction page
that I made the
a pre-filter wasn't
with a Skippy filter, and so for a couple of weeks
I totally bypassed the Bio-Force filter (luckily
I didn't remove it since I thought better not until
I had tried things out).
Well after researching some more, like I said I learnt
of other people saying their Skippy's were becoming
very glooped up with cruddy slimy waste, and more knowledgable
people saying its best to use a pre-filter to
cut out as much of that solid fishy waste as possible.
So I reconnected the Bio-Force back into place, and
now when I do a cleaning dump on the main bio-filter,
certainly not as much nasty looking gloop.
I just wish there was an easier way of cleaning
the Bio-Force. I still needed to clean it out
every 2 or 3 days because it gradually gets blocked
water slows to a trickle. While I'm quite used
to doing it, it is a bit of a pain
the coarse and fine foam rings, cleaning them out
thoroughly, and then putting them back, while also
being careful to
get the rubber sealing ring back in place without
trapping it, or it dropping into the casing and having
to open it up and retrieve it again! It's a fiddly
job, and in winter can be a very cold job too!
The one consolation is that I know it is catching
all that muck, and believe me, there is plenty.
Update for 2005
Do I still use a pre-filter / mechanical filter?
Yes, but I have now made
my own DIY pre-filter (June 2005), and
I have at last upgraded my pump to a Hozelock TITAN (see
below). But here is some history of how and why I decided
to build my own design of Pre-Filter.....
Before I built my Skippy-style bio-filter initially
I was using the Hozelock
UVC filter. As you've read you'll realise that I
fed up with cleaning this out, especially in the
summer, every 2 days
the water would absolutely STOP DEAD. It
would get so blocked up with
and fine particles in the foam sponge that no water
could get through at
Basically the Bio-Force UVC 2200 filter was not man
enough for my pond, even
though its a small pond! The ultra-violet light certainly
seemed more of
gimmick than anything because it never helped my
green-water problems, and
the foam filters in the unit just clogged up too
quickly. Bacteria NEVER
chance to breed or work in this manufactured filter
and there was never enough surface area for any bacteria
to cope with even my small pond.
It was just too small and I
was cleaning it out too regularly.
Cleaning the Hozelock
filter out was time-consuming, messy, cold and
Turn off the pump, unclip all the clips on the top,
lift up the top
sure not to bend the pipes too much (which invariably
out the foam filters (cold, wet, not fun), then put
it all back together,
sure the rubber seal was seated correctly (which
one time when we went on
holiday and my neighbour was left in charge, he didn't
do properly and the
nearly emptied dry!!), then re-clip the clips (which
are quite tough to
into place, and one clip broke off).
Anyway, when I had
first completed my DIY bio-filter, I decided (like
probably also wondering) to keep the Bio-force UVC
filter plumbed in just before my
Skippy bio-filter. So this was pre-filtering the
muck before the
meant I STILL had to clean it out every couple of
Now on the Skippy web site, they say that
they don't use a pre-filter as
emailed them about this, and they said that the
plastic or wire cage surrounding
in the pond is usually sufficient.
Well time went by, and
this winter just gone, one day when I was cleaning
Bio-Force filter, the plastic flexible hose leading
into it "gave
up". It was
brittle in the
winter cold, and had been bent too many times by
me lifting the lid of the
So I had no choice! The pipe was now too short to
lead into the Bio-Force
and it was too cold and I was too lazy to repair
it properly (I would need to dig up a
part of the the rockery to get to the pipe, refit
a new one, and re-plumb
So instead I went for a quick fix and cut and re-joined
the pipe directly to the
omitting the Bio-Force UVC filter altogether.
For several months my DIY bio-filter had been operating without a
mechanical pre-filter other than the plastic cage
that surrounds the pump in
main pond (and which you will read further below,
I had drilled a whole
of extra holes in the cage to allow water and muck
to pass through more
IMPORTANT: If you read my Design section
about the theory of the
explain that you get two types of bacteria aerobic and anaerobic.
bacteria are the good ones that really help the digestive
process of the
just like a sewage farm. Anaerobic is what results
in stagnant still
you do NOT want that kind. Anaerobic (bad)
bacteria might be more likely
occur without a pre-filter because it might allow
more fish poop to
accumulate in the bio-filter.
Now sewage farms use huge pumps and mixers to pump
air into the sewage
before it goes into the filter beds. So I
decided to use the same principle by adding
homemade Venturi at the top of my bio-filter.
It sucks air into the water,
bubbles which mix oxygen in, get passed down
into the heart of the bio-filter, then
up and out. I believe that this really helps
a lot. The waste solids can
sink to the
bottom for flushing out, and anaerobic bacteria
doesn't get a chance to
because 24 hours a day oxygen is being dissolved
into the water and passed
through the filter so encouraging mostly aerobic bacteria
So for the early poart of 2005 it all seems
fine. Yes I am getting some algae and blanket weed
while the pond develops its biological cycle,
but the water itself is
anything, even though it gets a good deal of
sunshine. I shall have to
summer to see how well it all copes. But I am confident. [Update
Nov 2005: At the very height of summer I got some
green water, and even then only after I cleaned the
bio-filter a little too excessively which disrupted
its biological process, but never has the green water
been as terribly bad as it had been in 2004].
Also note that I have stuck by my word of
not using any other kind of
commercially available chemicals to treat the
water. This is a totally
system. The only thing I do is boost the bacteria
by injecting some into
Skippy. Oh and make sure to use plenty of water
plants too which help the
balance and eat up extra nitrogen.
Re-Arranging the Filter Media
This year (2005) I have tried
something different. At the start of the year I
gave the bio-filter a total clean.
This is ok because it was still the cold time of
year when the bacteria are likely to be dead anyway.
When I put the green scouring pads back into the
filter I laid them carefully in a spiraling arrangement.
Whereas previously I had just chucked all the pads
time my thinking is to close the gaps up, making
its filtering process more efficient, and to also
encourage a slow rotating motion of the water as
it passes up through the filter pads. I made sure
the direction of the rotation was also the same
as that setup by the swirler pipes in the bottom
By laying the filter media pads carefully in this fashion
you are able to fit a lot more media into the bio-filter.
This means there is more surface area for bacteria to
colonise, and more bacteria means more efficient cleansing
These are the old, rectangular scrubbies after cleaning,
being laid in a spiralling, overlapping layout.
And similarly in the centre, always overlapping in
the same direction.
Finally I cut diagonally shaped scrubbies for the
last couple of layers at the top.
Here are the diagonal cut scrubbies in place, and
all ready to go.
And this is after about 3 months. The bacteria has
built up nicely in the bio-filter, and as you can
see there is algae growing on the top where it
is exposed to sunlight (this is ok and to be expected).
I still haven't put plants in the top yet. I keep
bio-filter pot looks as if its just a plant pot,
but I guess I just like fiddling with it too much!
Also notice my new Zik-style
the top which draws air down to aerate the water
it goes into the bio-filter. This extra
air oxygenates the water so that the "good" bacteria
can live and breed and do their stuff on all the
matter in the bio-filter.
big mistake I made, and would strongly advise other
newbies to pay attention to is to make
sure you buy an appropriately sized pump that is
not just for its immediate, but also future needs.
I have now (April 2005) purchased a Hozelock
Titan 8000 litres/hour solids handling pump,
but again here follows some history of my learning
The Hozelock Cyprio "Cascade" pumps
are really intended for small fountains and waterfalls.
Granted that is what I have, and to be fair it
suited the purpose at the outset, but now I've
crossed the threshold from requiring a pump with
fine filter cage, to needing one capable of pumping
solids, i.e. something more like the "Titan" range
So whats the difference?
Cascade vs. Titan
Well, the "Cascade" has
a plastic casing around the pump impeller that
prevents solids going up the tube to the fountain
because without this the fine holes of the fountain
spray-head would block very quickly. The pic below
shows the surround casing after removal from the
(which enables it to be cleaned). As you can see
the slots are reasonably fine, each
one is about 2mm wide, by 15mm long. They are intended
to keep out solids; fish waste, bits of leaves,
algae, blanket weed, etc. Which they do! But it
tends to clog up so much that eventually the flow
of water is inhibited. Then you have to lift it
out of the pond and clean it.
If your pond has
a fair bit of muck, and the fish constantly stir
it up, then the cage could block up within 3 or 4
power just a fountain spray head which does not
require much pressure then it would last quite
a while. However for my purpose, since
need a reasonable throughput of water, the reduction
in pressure soon tells.
Due to the evolution of my pond, I now need
to push those solid wastes out of the pond, and
my Cascade blocks up too quickly. I was having
to remove the actual Cascade pump unit from the pond every
3 or 4 days, let alone clean out the Bio-Force
filter every couple of days!
So I studied diagrams of the Titan pumps, and
looked at the spare impellers sold in my local
garden centre and compared ones for the Cascade,
with ones for the Titan (shown here).
I identified the following
- The Titan has a larger cylindrical filter cage
around the pump unit. This larger area will
allow a more even continuous flow of water into
cage, even when covered with a layer of blanket
- The Titan is advertised as being "eco-friendly"
with a Wild Life Protection System (WPS). What
this actually means is that there is a secondary
cage at the base of the unit with sliding slots
(look at the very bottom of the photo). When
fully open these slots are about 10mm wide
by 25mm high, but can be closed down to 2mm in
the spring to prevent small critters being sucked
up to an untimely demise! The lever to the left
of centre in the above photo is used to adjust
the slot size.
- The slots on the Titan are at the very base
of the pump which therefore is able to draw muck
the floor of the pond. This is much better
for the health of the pond, because silt settles
to the pond bottom where the pump can extract it.
- The impeller that actually does the pumping
is identical for both the Cascade and the Titan,
but for one thing. On the Cascade impeller there
is a sort of cap, which presumably helps make
impeller more efficient because it "draws" the
water better. On the Titan impeller this cap
which means that larger solids won't get
caught/trapped in the impeller device.
The Cascade 4000 impeller has a cap over the
impellor vanes. Water is drawn in from the front
(left-hand side of photo), and pushed out
of the sides. It's not intended for solids
like stones, snail
get trapped inside the cap.
The Titan 2000 and 3000 impeller is the same,
but without the cap.
Note the little lugs on the vanes which the
cap would fit on if included. Ok, its green
too: Green = Titan!
The Titan 5500 is however considerably larger
Having spent the best part of £140 now on two pumps,
the first rated at 2000litres/hour (440gallons/hour),
and the second at 4000litres/hour (880gph),
I now know I would have been far better obtaining a slightly
higher rated Titan with solids handling capability (perhaps
5500litres/hour model) right from the start. [I go into
the power aspect a little more on the Venturi
- don't just go for power. Consider the
additional function of
for your purposes.
What do I do? Until I can afford a Titan, I'm going to be
a tight old cheapskate
and modify my Cascade to emulate the Titan in "summer" mode.
Or in plain speaking terms, I am going to get out the cage from my old Cascade
2000 (its exactly the same size as the Cascade 4000), and butcher it by drilling
few extra 8mm holes all around the base so that it can draw in solids and more
water from the bottom. This photo shows the bottom of the cage before and after
drilled cage will be my Summer pump filter, and the original cage will be my
Winter/Spring pump filter.
How effective was it?
Well even the larger holes still block up over time,
but I have effectively increased the
amount of inlet space/surface area to feed into the pump.
The length of time between cage cleans has now extended
weeks. That'll do for me at least until I can afford a new
Titan 5500 (another £130!). And if something like
a stone or snail shell gets trapped under the Cascade impeller
cap, I will simply remove the cap as for a Titan impeller,
reduction in power.
[Sub-note: Stuff did start getting stuck
in the impellor cap, and because it was getting quite old
and worn I removed the cap from the impellor. The main
wear on the impellor was due to a small bush which got
one of its
cleanouts, which allowed the impellor cap to move too close
to the impellor housing which it then hit against and started
to crack the impellor cap. The damage was not as a result
of stones or snails, they would just get stuck in the impellor
and probably reduce its efficiency. I bet those snails
dizzy! Anyway there
was only a very slight reduction in the power after removing
Also available apparently is a Block Filter Extension.
This is a block of foam which can be attached to the front
pump as a pump pre-filter. I am sure this would
probably be yet more ineffective expense which would get
Disclaimer: You will in all likelihood invalidate your
warranty if you perform such butchery to your pump cage!
On the Bog
next thing to fix up is the bog-area of the stream. If you
remember, like fools we had removed all the overgrown Water-Musk.
So we got some new clumps of Common Reed or Norfolk
Reed (Phragmites australis) which is a top performer because
not only has it got a phenomenal growth rate in the right
conditions (don't get too many!!!), but it also oxygenates
the water; essential for many of the bacteria that need
Here we have re-planted the reeds, and some other varieties
of plants to get our natural "vegetable filter" going
Before new planting...